This invention relates to a mechanical Moslem calendar for an analog timepiece. It relates more particularly to a perpetual Moslem calendar for use in either the movement of a wrist watch or that of a clock.
The Moslem year is based on the moon's cycle and comprises about 354 solar days. The year is divided into 12 months of 29 and 30 days, and into weeks of 7 days of 24 hours. The odd months have 30 days and the even months 29, so that the year starts with a 30-day month and ends with a 29-day month.
In fact, the Moslem year lasts a little longer than 354 days. To compensate this difference, the last month of certain years of a 30-year correction cycle have 30 days instead of 29. Over this 30-year cycle, there are 19 so-called ordinary (or common) years of 354 days each and 11 so-called embolismic (or abundant) years of 355 days each. Actually, two 30-year cycles are used, each cycle being applied to a particular country or region. The two cycles, which start with year 1 and end with year 30, appear in the following table which only shows the embolismic years:
Cycle I: 2, 5, 7, 10, 13, 15, 18, 21, 24, 26 and 29
Cycle II: 2, 5, 7, 10, 13, 16, 18, 21, 24, 26 and 29
The two cycles differ from one another in that in the first the 15th year is an embolismic year and the 16th is an ordinary year whereas it is the other way round in the second.